A uniform <i>p</i>CO<sub>2</sub> climatology combining open and coastal oceans

Abstract

<jats:p>Abstract. In this study, we present the first combined open and coastal ocean pCO2 mapped monthly climatology (Landschützer et al. (2020), doi:10.25921/qb25-f418, https://www.nodc.noaa.gov/ocads/oceans/MPI-ULB-SOM_FFN_clim.html) constructed from observations collected between 1998 and 2015 extracted from the Surface Ocean CO2 Atlas (SOCAT) database. We combine two neural network-based pCO2 products, one from the open ocean and the other from the coastal ocean, and investigate their consistency along their common overlap areas. While the difference between open and coastal ocean estimates along the overlap area increases with latitude, it remains close to 0 μatm globally. Stronger discrepancies, however, exist on the regional level resulting in differences that exceed 10 % of the climatological mean pCO2, or an order of magnitude larger than the uncertainty from state of the art measurements. This also illustrates the potential of such analysis to inform the measurement community about the locations where additional measurements are essential to better represent the aquatic continuum and improve our understanding of the carbon exchange at the air water interface. A regional analysis further shows that the seasonal carbon dynamics at the coast-open interface are well represented in our climatology. While our combined product is only a first step towards a true representation of both the open ocean and the coastal ocean air-sea CO2 flux in marine carbon budgets, we show it is a feasible task and the present data product already constitutes a valuable tool to investigate and quantify the dynamics of the air-sea CO2 exchange consistently for oceanic regions regardless of its distance to the coast. </jats:p>

Net Community Production and Inorganic Carbon Cycling in the Central Irminger Sea

“…While gas exchange has very little impact on the overall mixed layer DIC concentration, the average total addition of DIC to the mixed layer due to CO 2 influx from the atmosphere is 2.1 mol ± 1.1 mol m −2 yr −1 over our 7 year period. A recent p CO 2 climatological product reports a mean of 3.0 ± 0.7 mol m −2 yr −1 during our study period (range 2.1–3.8 mol m −2 yr −1 , Landschützer et al., 2020). This matches our observations within the uncertainty, and the somewhat higher values can likely be attributed to our differing choice of gas transfer parameterization (Atamanchuk et al., 2020).…”

Reconstruction of global surface ocean pCO&lt;sub&gt;2&lt;/sub&gt; using region-specific predicators based on a stepwise FFNN regression algorithm

“…However, the stepwise-FFNN product suggested lower pCO2 average values in the Arctic and higher values in the Southern Ocean near the Antarctic continent. Compared with previous climatology product (Landschützer et al, 2020), the global distribution pattern of surface ocean pCO2 was basically well consistent. Inconsistent spatial distribution also existed in the Arctic and parts of the Southern Ocean near the Antarctic continent.…”

Improved Quantification of Ocean Carbon Uptake by Using Machine Learning to Merge Global Models and pCO2 Data

“…The LDEO-HPD product covers 89.6% of the total ocean area, leaving out the Arctic and coastal zones. Before estimating the net carbon flux from observation-based products, we use the method of to fill spatial gaps in the pCO 2 product with climatology (Landschützer, Laruelle, et al, 2020) plus the global-mean trend. This fills in the 10.4% to create a global gap-free product.…”